KR19990072089A - Biaxially Oriented Polyester Film for Metal Plate Bonding Processing - Google Patents

Abstract

The present invention relates to (a) at least 82 to 100 mol% of terephthalic acid and 2,6-naphthalenedicarboxylic acid or 2,6-naphthalenedicarboxylic acid and other dicarboxylic acids (to the total amount of all dicarboxylic acid components) S) 0-18 mol% or less and (b) ethylene glycol 82-100 mol% or more and cyclohexanedimethanol or cyclohexanedimethanol in combination with other diols relative to the total amount of all diol components 0-18 The present invention relates to a biaxially oriented polyester film for metal plate bonding molding, which is composed of mol% or less and (c) a glass transition temperature of 78 ° C. or higher and (d) a copolymerization polyester having a melting point of 210 to 250 ° C. The film has the following relationship between the highest temperature peak temperature (Te, ℃) and the glass transition temperature (Tg, ℃) of the loss modulus: Te-Tg ≤ 30, or the content of free dicarboxylic acid diol ester is 50 ppm The film below has improved moldability, heat resistance, and clean resistance, while maintaining improved moldability of the contents, especially after retort treatment.

Description

Biaxially Oriented Polyester Film for Metal Plate Bonding Molding

Metal cans are generally coated on their inner and outer surfaces to prevent corrosion. In recent years, the development of a method for achieving corrosion resistance without using an organic solvent has been accelerated for the purpose of streamlining the process, improving hygiene and preventing pollution. As one of these methods, it has been attempted to coat a metal can with a thermoplastic film.

That is, research is being conducted on a method for producing a can by bonding a thermoplastic resin film onto a metal plate such as a tin plate, steel without tin, and aluminum, and then drawing the bonded metal plate.

From the standpoint of molding processability, heat resistance, impact resistance and directivity, it becomes increasingly clear that the copolyester film is suitable for use as the thermoplastic resin film. However, the polyester film does not always show sufficient flavor, and when the cans coated with it contain beverages in which very subtle tastes are important, such as green tea or colorless odorless, such as mineral water, they do not always show a change in flavor. Is detected.

Japanese Patent Laid-Open No. 6-116376 proposes a polyester film which is bonded and molded on a metal plate, which is made of a copolyester polyester containing an alkali metal element and a geranium element in a specific amount and having improved steering properties. When the container containing the contents is not heated, the film shows excellent complementary properties in the case of a cold pack system, but when the container containing the contents is subjected to a heat treatment such as a retort treatment, It does not always indicate sufficient complementarity.

Japanese Unexamined Patent Application, First Publication No. Hei 8-231690 proposes a co-polyester film comprising 1,4-cyclohexanedimethanol and ethylene glycol in a specific range of ratios as terephthalic acid and diol as main acid components. Although the film has been proposed to be able to obtain steering properties for contents requiring retort treatment, it is not possible to obtain a can with sufficient can manufacturing properties due to its low heat resistance.

It is an object of the present invention to overcome the drawbacks of conventional techniques, while maintaining the excellent moldability, heat resistance and impact resistance of the copolyester film, while improving the steering properties of the contents, in particular, the steering after finishing retort treatment, It is to provide a polyester film for molding.

Other objects and advantages of the present invention will become more apparent with the following description.

The present invention relates to a polyester film bonded to a metal plate and molded. More specifically, beverage cans, which exhibit excellent molding processability when the can is manufactured by deep drawing a metal plate bonded with a film, and have excellent heat resistance, retort resistance, steering resistance, impact resistance and corrosion resistance. The present invention relates to a polyester film bonded and molded on a metal plate capable of making cans such as food cans.

According to the present invention, firstly, the above objects and advantages of the present invention,

(A) (a) 82 to 100 mol% of terephthalic acid and 2,6-naphthalenedicarboxylic acid or 2,6-naphthalenedicarboxylic acid and other dicarboxylic acid (s) relative to the total dicarboxylic acid component A combination of 0 to 18 mol% of (b) and 82 to 100 mol% of ethylene glycol and 0 to 18 mol% of a combination of cyclohexanedimethanol or cyclohexanedimethanol with other diols, with respect to the total diol component, c) a copolymer of polyester having a glass transition temperature of 78 ° C. or higher and (d) a melting point of 210 to 250 ° C.,

(B) The following relationship between the highest temperature peak temperature (Te, ° C) and the glass transition temperature (Tg, ° C) of the loss modulus:

Te-Tg ≤ 30

It is to provide a biaxially oriented polyester film for metal plate bonding molding processing having.

The copolyester of the present invention is a combination of terephthalic acid with 82 to 100 mol% and 2,6-naphthalenedicarboxylic acid or 2,6-naphthalenedicarboxylic acid and other dicarboxylic acids with respect to the total dicarboxylic acid component. 0 to 18 mol%.

Specific examples of other dicarboxylic acids include aromatic dicarboxylic acids such as isophthalic acid and phthalic acid; Aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, decandicarboxylic acid and the like; Alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid and the like; Etc. are included. These may be used alone or in combination of two or more.

The copolyester of the present invention comprises 82 to 100 mol% of ethylene glycol and 0 to 18 mol% of a combination of cyclohexanedimethanol or cyclohexanedimethanol and other diols with respect to the total diol component.

Specific examples of other diols include aliphatic diols such as diethylene glycol, propylene glycol, neopentyl glycol, butanediol, pentanediol, hexanediol, and the like; Alicyclic diols such as cyclohexanedimethanol; Aromatic diols such as bisphenol A and the like; And polyalkylene glycols such as polyethylene glycol, polypropylene glycol, and the like. These may be used alone or in combination of two or more.

The copolyester may comprise at least one or both of 2,6-naphthalenedicarboxylic acid and 1,4-cyclohexanedimethanol as copolymerization components.

Particularly preferably, all the dicarboxylic acid components of the copolyester are composed of terephthalic acid and 2,6-naphthalenedicarboxylic acid and all of the diol components are composed of ethylene glycol.

In the present invention, the copolyester has a glass transition temperature (Tg) of 78 ° C or higher and a melting point of 210 to 250 ° C.

If Tg is lower than 78 ° C., when the film of the present invention is bonded to a metal plate and molded into a metal can, the heat resistance will be deteriorated, and the bomi-deflection property will be reduced after the retort treatment. In order to increase the Tg of the copolyester of the present invention above 78 ° C., 2,6-naphthalenedicarboxylic acid and cyclohexanedimethanol are used as copolymer components, as described above.

The glass transition temperature (Tg) of the copolyester is preferably in the range of 78 to 90 ° C.

The Tg of polyester was measured by placing 20 mg of a film sample in a DSC measuring pan, heating and melting the film sample in a heated state at 290 ° C. for 5 minutes, and then quenching and solidifying the pan on an aluminum foil placed on ice. It uses and measures at a temperature increase rate of 20 degree-C / min.

When the melting point is lower than 210 ° C., the heat resistance of the polymer will be worse, and when the melting point is higher than 245 ° C., the crystallinity of the polymer will be so high that moldability will be impaired.

The melting point of the copolyester is preferably in the range of 210 to 245 ° C.

The melting point of the copolymerized polyethylene terephthalate is measured by a method of determining the melting peak at a room temperature rate of 20 ° C./min using Du Pont Instruments 910 DSC. The amount of sample is 20 mg.

The intrinsic viscosity (at 35 ° C. in orthochlorophenol) of the copolyester is preferably in the range of 0.52 to 1.50, more preferably 0.57 to 1.00, particularly preferably 0.60 to 0.80. If the intrinsic viscosity is less than 0.52, the impact resistance will be disadvantageously insufficient. On the other hand, if the intrinsic viscosity is greater than 1.50, moldability may be impaired.

Although the copolyester of the present invention is not limited by the above production method, as a preferred method of producing the desired copolyester, the desired degree of polymerization of the reaction product after esterifying the terephthalic acid, ethylene glycol and the copolymerizable component A method comprising polycondensation reaction until obtained, or a method comprising transesterifying terephthalic acid dimethyl ester, ethylene glycol and a polymerizable component and then polycondensing the reaction product until the desired degree of polymerization is obtained. . The copolyester obtained by one of the above methods (melt polymerization) can be converted into a polymer having a high degree of polymerization by polymerizing in a solid state (solid phase polymerization) as necessary.

The copolyester may contain additives such as antioxidants, heat stabilizers, viscosity modifiers, plasticizers, color modifiers, lubricants, nucleating agents and ultraviolet absorbers as needed.

Preferred examples of the catalyst used in the polycondensation reaction include antimony compounds (Sb compounds), titanium compounds (Ti compounds), geranium compounds (Ge compounds) and the like. Among them, a geranium compound and a titanium compound are more preferable in view of the film's directivity. Preferred titanium compounds include titanium tetrabutoxide and titanium acetate. Preferred geranium compounds include (a) amorphous geranium oxides, (b) fine crystalline geranium oxides, (c) solutions containing geranium oxides dissolved in glycol in the presence of alkali metals, alkaline earth metals or compounds thereof, (d) a solution containing geranium oxide dissolved in water, and the like. The amount of catalyst used may be an amount generally used.

Co-polyester preferably contains a lubricant in order to improve the winding property of a film. The lubricant is either organic or inorganic, but is preferably inorganic. Specific examples of the inorganic lubricant include silica, alumina, titanium oxide, calcium carbonate, barium sulfate, and the like, and specific examples of the organic lubricant include silicone resin particles, crosslinked polystyrene particles, and the like. The lubricant is preferably a monodispersed lubricant having a particle diameter ratio (long diameter / short diameter) of 1.0 to 1.2 in terms of pin hole resistance. Specific examples of the monodispersed lubricant include spherical silica, spherical silicone resin particles, spherical crosslinked polystyrene, and the like.

The particle diameter and amount of the lubricant are determined by the winding property, pinhole resistance and complementary complement property of the film. That is, by adding silica having an average particle size of 1.5 μm to 0.06% by weight or more and 0.25% by weight or less, or adding silica having an average particle size of 0.8 μm to 0.1% by weight or more and 0.45% by weight or less, impaired complementarity Winding property can be protected without making it.

The lubricant is not limited to the externally added particles, and may be, for example, internally precipitated particles obtained by precipitation in part or in the previous step of the catalyst used in the preparation of the polyester. In addition, both externally added particles and internally precipitated particles can be used.

A polyester film of the invention, which is particularly suitable for food or beverage cans, the smaller the amount of substance dissolved or dispersed from the film, the better the polyester film. However, it is virtually impossible to completely remove these materials. Therefore, in order to use the polyester film of the present invention as a food or beverage can, for example, the amount of material extracted with ion-exchanged water at 121 ° C. for 2 hours is preferably 0.5 mg or less, more preferably, per square inch of film. 0.1 mg or less.

The film of this invention consists of said copolyester, and is used in biaxial orientation and a heat setting state. The highest peak temperature (Te) and glass transition temperature of the loss modulus of the polyester film measured by DSC are required to satisfy the following formula.

Te-Tg ≤ 30

When the value of Te-Tg exceeds 30, the molecular orientation and crystallinity of the film become too high, and the molding processability greatly decreases. The Te value is a value different depending on the copolymer component and the copolymerization ratio, and is preferably controlled by the film forming conditions, in particular, the magnification or stretching temperature in biaxial stretching.

The relationship between the hottest peak temperature Te of the loss modulus and the glass transition temperature Tg is preferably 15 ≦ Te−Tg ≦ 25.

In the above equation, Te is obtained at a measuring frequency of 10 Hz and a dynamic displacement of ± 25 × 10 ^-4 cm using a dynamic viscoelasticity measuring device.

The polyester film of the present invention preferably has the following relationship between the surface 100 and the surface 110 parallel to the film surface:

0.10 ≤ I (110) / I (100) ≤ 0.40

[Wherein I 110 is the X-ray diffraction intensity obtained from the surface 110 and I (100) is the X-ray diffraction intensity obtained from the surface 100].

If the strength ratio I (110) / I (100) is less than 0.10, moldability will be insufficient. On the other hand, if the strength ratio is more than 0.40, the thermal resistance will be easily damaged.

In addition, the polyester film of the present invention preferably has a refractive index of 1.620 to 1.670, more preferably 1.625 to 1.665 in all film surface directions. In deep or cross-processing, which is often used in can manufacturing, the deformation must be uniform in all directions and any part of the film must be able to comply with the deformation. If the film surface omnidirectional refractive index is less than 1.620, the moldability is satisfactory, but the heat resistance tends to be poor. On the other hand, if the refractive index is higher than 1.670, the film will be easy to whiten or break during deep processing due to poor moldability.

In addition, the polyester film of the present invention preferably has a plane orientation coefficient of 0.100 to 0.150, more preferably 0.110 to 0.140.

If the plane orientation coefficient is less than 0.100, the film will undesirably crack the film at deep drawing with high draw ratio. On the other hand, if the plane orientation coefficient is greater than 0.150, the film is incapable of fracture due to deep cross-linking.

Here, the "plane orientation coefficient" is defined by the following formula.

f = [(n _x + n _y ) / 2]-n _z

[Wherein f is a plane orientation coefficient and n _x , n _y and n _z are refractive indices in the transverse, longitudinal and thickness directions of the film, respectively].

The refractive index is measured according to the following method.

Attach the polarization analyzer to the eyepiece side of the Abbe precipitation system and measure the precipitation rate with monochromatic NaD line. Methylene iodide is used as a mounting liquid and the measurement temperature is 25 ° C.

The polyester film of the present invention is different from the melting peak (so-called "sub" in DSC in the temperature range of preferably 150 to 205 ° C, more preferably 155 to 200 ° C, particularly preferably 160 to 195 ° C. Sub-peak "). The sub-peak contributes to film quality stability after heat bonding the film onto the metal plate. If the sub peak is present at a temperature of less than 150 ° C, the bottom portion of the can tends to be brittle when the heat bonding temperature rises on the metal plate, and the film tends to break when the heat bonding temperature decreases. Therefore, it is difficult to make a good can by adjusting the heat bonding temperature. If the sub-peak is present at a temperature above 205 ° C., it can be easily broken at any heat bonding temperature during can production, thus making cans difficult.

The sub-peak temperature is measured according to the method of obtaining the sub-peak with a sample amount of 20 mg at a heating rate of 20 ° C./min using a Du Pont Instruments 910 DSC as in the melting point measurement. As used herein, the term "subpeak" refers to the small peak B that appears on the low temperature side of the melting peak A of the DSC chart.

The polyester film of the present invention preferably has a tensile stress (F40, kgf / mm ² ) at 40% elongation at 100 ° C. and a tensile stress at 120% elongation at 100 ° C. between film surface directions (F120). , kgf / mm ² )

0.6 ≤ F40 / F120 ≤ 0.8.

Tensile stress (kg / mm ² ) at 40% and 120% elongation at 100 ° C. was measured using a tensile tester with a heating probe, measuring temperature of 100 ° C., chuck spacing 10 cm, and tensile speed 10 When pulling a 10 mm-wide flat sample under the condition of cm / min, it is defined as the respective tensile stress (kg / mm ² ) at 40% and 120% extension. This direction often matches the extrusion direction of the film.

The tensile stress at 100 ° C. can be controlled by the kind and amount of copolymer components or the tensile conditions of the film. When F40 / F120 is less than 0.6, the moldability caused by molding is greatly increased, so moldability is likely to decrease, whereas when F40 / F120 is more than 0.8, the impact resistance is likely to be poor because the film tends to embrittle. will be.

The polyester film of the present invention is melt-extruded co-polyester, and the extrudate is quenched to obtain an unstretched film, the unstretched film in the longitudinal direction at a temperature of 95 to 150 ℃, preferably 110 to 140 ℃ Biaxially stretched from 2.5 to 3.8 times, preferably from 2.7 to 3.6 times, and from 2.7 to 4.0 times, preferably from 2.8 to 3.8 times in the transverse direction at a temperature of from 100 to 150 ° C., preferably from 110 to 140 ° C. It is prepared by heat-setting a biaxially oriented film at 230 ° C, preferably 140 to 210 ° C. The longitudinal stretching magnification, the lateral stretching magnification and the heat setting temperature are appropriately selected to meet the predetermined values of the characteristic values.

The refractive index in the film thickness direction of a polyester film becomes like this. Preferably it is 1.500-1.545, More preferably, it is 1.505-1.530. If the refractive index is too low, the moldability will be insufficient, whereas if the refractive index is too high, the heat resistance may be lowered because the film has an almost amorphous structure.

According to the present invention, there is provided in particular a biaxially oriented polyester film for metal plate bonding molding having improved steering complementarity after retort treatment.

According to a study conducted by the inventors of the present invention, although the film is made from the same copolyester as the copolyester used in the present invention, although the relationship between Te and Tg does not always hold, after the retort treatment It has been found that complementarity can be improved like the film when the content of free dicarboxylic acid diol ester is 50 ppm or less.

Thus, according to the invention, secondaryly,

(A) (a) 82 to 100 mol% of terephthalic acid and 2,6-naphthalenedicarboxylic acid or 2,6-naphthalenedicarboxylic acid and other dicarboxylic acid (s) relative to the total dicarboxylic acid component Combination of 0 to 18 mol%, (b) 82 to 100 mol% of ethylene glycol and 0 to 18 mol% of a combination of cyclohexanedimethanol or cyclohexanedimethanol with other diols, relative to the total components, and ( c) a copolymer of polyester having a glass transition temperature of 78 ° C. or higher and (d) a melting point of 210 to 250 ° C.,

A biaxially oriented polyester film (hereinafter referred to as " secondary polyester film of the present invention ") for metal plate bonding molding processing, containing (B ') free dicarboxylic acid diol ester in an amount of 50 ppm or less.

In the free dicarboxylic acid diol ester (hereinafter referred to as "free glycol ester") contained in the secondary polyester film of the present invention, the acid component of the copolyester is terephthalic acid and 2,6-naphthalenedicarboxylic acid, and glycol When the component is ethylene glycol, it is free bis (β-hydroxyethyl) terephthalate (hereinafter abbreviated as BHET) and free bis (β-hydroxyethyl) naphthalate (hereinafter abbreviated as BHEN). In this case, therefore, the content of the dicarboxylic acid diol ester contained in the film is the total amount of the BHET and BHEN contained in the film. In particular, the content of BHEN is small in the range of the composition of the polymer-component of the present invention. In particular, when the molar ratio of the acid component (terephthalic acid / 2,6-naphthalenedicarboxylic acid) is in the range of 85/15 to 97/3, the content of BHEN contained in the film is lower than the quantitative detection limit, and substantially BHET Only is detected as free glycol ester. In addition, the total content of free glycol ester contained in the film can be advantageously reduced by selecting the composition of the polymer-constituent, such that only BHET is substantially detected as the free glycol ester.

The content of the free glycol ester contained in the film should be reduced to 50 ppm or less, preferably 30 ppm or less, more preferably 20 ppm or less.

If the content of the free glycol ester contained in the secondary polyester film of the present invention is more than 50 ppm, the replenishment of the can contents after retort sterilization will be greatly reduced. In order to reduce the amount of free glycol ester contained in the polyester film to 50 ppm or less, the above described range of the composition of the polymer-component must be satisfied.

Although the secondary polyester film of the present invention is not limited by the manufacturing method of the copolyester, from the viewpoint of complementarity, it is preferable that the total amount of the alkali metal elements contained in the film satisfies A ≦ 5 (ppm) (A : Total amount of alkali metal elements). The total amount of alkali metal elements is the sum of the ppm values of Li, Na, and K elements quantified by atomic absorption analysis.

When the total amount of alkali metal elements is 5 ppm or less, the amount of ether glycol produced by production of the copolyester, in particular, the amount of by-product diethylene glycol will increase, and the heat resistance of the polyester film will be lowered, and further polyester It is already known that the productivity of the electrostatic applied cast method of a film will be reduced. However, from the studies carried out by the inventors of the present invention, the amount of by-product ether glycol, in particular the amount of by-product diethylene glycol, in the preparation of the copolyester is determined by the amount of the metal compound serving as the catalyst and the conditions of the esterification reaction or the transesterification reaction. It can be controlled by optimizing, and the reduction of the productivity of the electrostatically applied cast method of the polyester film is within a certain range of the ratio of the amount of the catalytic metal element derived from the metal compound to the amount of the phosphorus element derived from the phosphorus compound in the film. It has been found that it can be suppressed by limiting to.

The "catalyst metal element" used in the present invention refers to one derived from a metal compound used as a reaction catalyst. The metal element is present in the state dissolved in the copolyester and must be distinguished from the metal atoms contained in the lubricant particles. A "phosphorus compound" is derived from a phosphorus compound which inactivates the catalyst or is used as a stabilizer of the copolyester.

In the secondary polyester film of the present invention, the sum of the concentration (M) of the catalytic metal element and the concentration (P) of the phosphorus element remaining in the film is preferably in the range of 20 ≦ (M + P) ≦ 55 (mmol%). . If (M + P) is less than 20 mmol%, the productivity of the electrostatic applied cast method of the copolyester will be lowered. If (M + P) is greater than 55 mmol%, heat resistance may be lowered due to an increase in the amount of by-product ether glycol.

In addition, the secondary polyester film of the present invention has a concentration ratio of the catalytic metal element concentration (M) to the phosphorus element concentration remaining in the film in the range of 1? (M / P)? 5 (mmol% / mmol%). If the M / P is less than 1 or greater than 5, the balance between the catalytic metal element and the phosphorus element will be lost, and excess phosphorus element or catalytic metal element may be present in the polymer, thereby degrading thermal stability.

The secondary polyester film of the present invention preferably has a catalytic metal element remaining in the film in the range of 10 ≦ M ≦ 35 (mmol%). If M is less than 10 mmol%, it is difficult to obtain a copolyester having sufficient degree of polymerization, and properties such as impact resistance may be lowered. If M is more than 35 mmol%, thermal stability may be lowered.

The copolymerized polyester of the present invention preferably contains at least 90 mol% of ethylene glycol with respect to the total amount of all diol components, and preferably at most 5 mol% of diethylene glycol copolymerized with copolymerized components with respect to the total diol components. More preferably 4 mol% or less. If it exceeds 5 mol%, heat resistance may be lowered. Here, diethylene glycol includes diethylene glycol by-produced in the manufacture of copolyester containing ethylene glycol as a glycol component. The amount of copolymerized diethylene glycol is preferably 0.5 mol% or more (relative to the total glycol component) from the viewpoint of producing the copolymerized polyester.

The intrinsic viscosity of the copolyester is preferably 0.5 to 0.8 dl / g.

In the secondary polyester film of the present invention, the extract per square inch of the film is preferably 0.1 mg or less when immersed in ion-exchanged water and extracted at 125 ° C. for 1 hour.

The secondary polyester film of the present invention preferably has the following relationship between Te and Tg, as in the polyester of the present invention.

Te-Tg ≤ 30

Although not described herein, it should be understood that the secondary polyester film of the present invention has the same properties or performance as the polyester film.

All polyester films of the present invention preferably have a thickness of 6 to 75 μm, more preferably 8 to 75 μm, particularly preferably 10 to 50 μm. If the thickness is less than 6 μm, the film breaks easily during molding and if the thickness is more than 75 μm, it is uneconomical with excess quality.

The metal plate bonded to the polyester film of this invention, especially the metal plate for can manufacture, is advantageously a tin plate, a steel without tin, aluminum, etc. The polyester film can be bonded onto the metal plate by the following method. (1) The metal plate is heated at a temperature equal to or higher than the melting point of the film, bonded to the film, and then cooled to bring the surface layer portion (thin layer portion) of the film into contact with the amorphous metal plate to closely bond the film to the metal plate. (2) The primer is previously coated on the film forming the adhesive layer, and the film is bonded to the metal plate by a method of bonding the adhesive layer to the metal plate. Known resin adhesives such as epoxy based adhesives, epoxy-ester based adhesives and alkyd based adhesives can be used to form the adhesive layer.

In the following Examples, the present invention is described in detail. The properties in the examples were measured by the following method.

(1) intrinsic viscosity of polyester

Measured in ortho-chlorophenol at 35 ° C.

(2) melting point of polyester

Using a Du Pont Instruments 910 DSC, the melt peaks of the samples are determined at a rate of 20 ° C./min. Sample amount is 20 mg.

(3) glass transition temperature (Tg) of polyester

20 mg of film sample was placed in a DSC measurement pan, heated for 5 minutes on a 290 ° C. heating stage, and then the sample pan was quenched and solidified on an aluminum foil placed on ice, resulting in a Du Pont Instruments 910 DSC at an elevated temperature of 20 ° C./min Use to find the glass transition point.

(4) Highest peak temperature (Te) of loss modulus of film

Using a dynamic viscoelasticity measuring device, the loss modulus is determined at a measurement frequency of 10 Hz and a dynamic displacement of ± 25 × 10 ⁻⁴ cm, and the highest temperature peak temperature is measured at this point.

(5) Deep drawability

The film is bonded to both sides of a 0.25 mm-thick tin free steel sheet heated at a temperature above the melting point of the polyester, cooled with water and then cut into 150 mm-diameter disk-shaped pieces. The disc-shaped pieces are deepened in four steps using drawing dice and punches to create 55 mm-diameter sideless wood containers (weakly referred to as "cans"). The cans were observed and the following items evaluated according to the following criteria.

(a) Deep Processing-1

○: The film is normal, and the processed film is not whitened or broken.

(Triangle | delta): The upper part of the can of a film is whitened.

X: A part of film breaks.

(b) Deep Processing-2

(Circle): The film is shape | molded appropriately, and the corrosion value test of the film bonded to the inner surface of a can shows the electric current value of 0.2 mA or less (The electric current value is filled with a 1% NaCl aqueous solution, and an electrode is inserted between cans. It is measured when the can is used as an anode and a voltage of 6 V. This test is hereinafter referred to as "ERV test".

X: The film is normal but exhibits a current value of 0.2 mA or more in the ERV test. When the electric conducting part is expanded and observed, pinhole-like cracks starting from the coarse lubricant are observed.

(6) impact resistance

After good canning, the cans are filled with water, cooled to 0 ° C., and in each test 10 cans are dropped to the bottom of the polyvinyl chloride-tile at a height of 30 cm. Afterwards, the inside of each can is ERV tested.

(Circle): The current value of the film of all 10 cans is 0.2 mA or less.

(Triangle | delta): The current value of the film of 1-5 cans is 0.2 mA or more.

X: The current value of the film of 6 or more cans was 0.2 mA or more, or the crack of the film was already observed after dropping.

(7) Heat Saturation Resistance

The can with good deep bridge molding is heated at 200 ° C. for 5 minutes, and the impact resistance is evaluated in the same manner as described in the above (3).

(Circle): The current value of all 10 cans is 0.2 mA or less.

(Triangle | delta): The current value of the film of 1-5 cans is 0.2 mA or more.

X: The current value of the film of 6 or more cans is 0.2 mA or more, and the crack of the film was already observed after heating at 200 degreeC for 5 minutes.

(8) Retort Resistance

Cans with good cardiac formation are filled with water, retorted in a steam sterilizer at 120 ° C. for 1 hour and then stored at 50 ° C. for 30 days. In each test 10 cans are dropped to the polyvinyl chloride-tile bottom at a height of 50 cm, after which the inside of each can is subjected to an ERV test.

(Circle): The current value of the film of all 10 cans is 0.2 mA or less.

(Triangle | delta): The current value of the film of 1-5 cans is 0.2 mA or more.

X: The current value of the film of 6 or more cans was 0.2 mA or more, or the crack of the film was already observed after dropping.

(9) Bomi Sung-1

Cans with good cardiac molding are filled with ion-exchanged water and stored at room temperature (20 ° C) for 30 days. Thirty panels were sampled using the immersion solution and compared with the comparative ion exchange water. The lubricity of the film is evaluated based on the following criteria.

(Double-circle): The panel of 3 or less of 30 persons felt the change of taste compared with the comparative liquid.

(Circle): The panel of 4-6 of 30 person felt a change of taste compared with the comparative liquid.

(Triangle | delta): The panel of 7-9 of 30 persons felt the change of taste compared with the comparative liquid.

X: The panel of ten or more of 30 persons felt the change of taste compared with the comparative liquid.

(10) Bomi Sung-2

Cans with good cardiac molding are filled with ion-exchanged water, retorted in a steam sterilizer at 120 ° C. for 1 hour, and then stored at room temperature (20 ° C.) for 30 days. Thirty panels were sampled using the immersion solution and compared with the comparative ion exchange water. The lubricity of the film is evaluated based on the following criteria.

(Double-circle): The panel of 3 or less of 30 persons felt the change of taste compared with the comparative liquid.

(Circle): The panel of 4-6 of 30 person felt a change of taste compared with the comparative liquid.

(Triangle | delta): The panel of 7-9 of 30 persons felt the change of taste compared with the comparative liquid.

X: The panel of ten or more of 30 persons felt the change of taste compared with the comparative liquid.

(11) Tensile stress at 40% and 120% elongation at 100 ° C (F40, F120)

Tensil samples, 10 mm wide, were measured using a tensile tester (Tensilon Universal Tensile Tester, Tokyo Baldwin Co., Ltd.) with a heating probe, measuring temperature 100 ° C., chuck spacing 10 cm and tensile speed 10 When the tensile test is performed under the condition of cm / min, the stress (kg / mm ² ) at elongation 40% and 120% is obtained.

(12) X-ray diffraction intensity ratio

CuK-α as an X-ray source and subjected to multiple peel separations using the Pseudo Voight Fill model, with a diverging slit 1/2 °, a scattering slit 1/2 °, a light receiving slit 0.15 mm and a scanning speed of 1,000 ° / min Accordingly, by measuring the X-ray diffraction intensity (I (100)) obtained at the surface 100 parallel to the film surface and the X-ray diffraction intensity (I (110)) obtained at the surface 110 parallel to the film surface Obtain the X-ray diffraction intensity ratio from (I (110)) / (I (100)).

(13) Refractive Index in Film Surface Direction and Film Thickness Direction

A polarization analyzer is attached to the eyepiece side of the Abbe refractometer, and the refractive index is measured in this direction by a monochromatic NaD line. Methylene iodide is used as the mounting liquid and the measurement temperature is 25 ° C.

(14) plane orientation coefficient

A polarization analyzer was attached to the eyepiece side of the Abbe refractometer, and each of the refractive indices n _x , n _y and n _z in the longitudinal, transverse and thickness directions of the film was measured by NaD lines, and the plane orientation coefficient f was obtained from the following equation.

f = [(n _x + n _y ) / 2]-n _z

(15) Sub-peak in DSC

Subpeaks are measured using a Du Pont Instruments 910 DSC at a heating rate of 20 ° C / min. The amount of sample is 20 mg.

(16) Amount of Free Glycol Ester

500 mg of the polyester film are dissolved in 3 ml of hexafluoroisopropanol. 10 ml of methanol is added to the solution, the sample polymer is reprecipitated, and the concentration in the film is determined by directly measuring the amount of free glycol ester by liquid chromatography using the filtrate after filtration. Since the amount of free BHEN in the examples of the present invention is below the quantitative limit, the amount of free glycol ester substantially represents the amount of free BHET.

(17) Water extraction quantity -1

The polyester film is immersed in ion-exchanged water and extracted at 121 ° C. for 1 hour. The extract contained in the immersion liquid is measured to determine the amount of extract per square inch of the film.

(18) Water extraction volume-2

The polyester film is immersed in ion-exchanged water and extracted at 125 ° C. for 1 hour. The extract contained in the immersion liquid is measured to determine the amount of extract per square inch of the film.

(19) alkali metal content

The film sample is dissolved in ortho-chlorophenol and then the extraction operation is performed with 0.5 N hydrochloric acid. The amounts of Na, K and Li contained in the extract are quantified by analyzing the atomic absorbance, respectively.

(20) Catalytic metal element content and phosphorus element amount

The film sample is melted at 240 ° C. to make a circular disk, and the amount of catalytic metal and phosphorus are quantified by fluorescence X-ray analysis.

(21) bonding

The polyester film is bonded onto a 0.25 mm-thick tin free steel sheet heated at a temperature above the melting point of the polyester and cooled to form a film-coated steel sheet. The film-coated steel sheet was observed to evaluate the bondability according to the following criteria.

[Air Bubble and Wrinkle Criteria]

(Circle): Bubble and a wrinkle are not observed.

Δ: 2 or 3 bubbles or wrinkles are observed per 10 cm.

X: Many bubbles and wrinkles are observed.

[Judgement criteria of heat shrinkage rate]

○: shrinkage is less than 2%.

(Triangle | delta): Shrinkage is 2% or more and less than 5%.

X: Shrinkage is 5% or more.

Examples 1 to 7 and Comparative Examples 1 to 3

The unstretched film was dried, melt-extruded and quench-solidified by copolymerizing polyethylene terephthalate (containing 0.2 wt% of spherical silica having a specific viscosity of 0.64, a particle size ratio of 1.1 and an average particle diameter of 0.5 μm) prepared by copolymerizing the components shown in Table 1. Make. The unstretched film is stretched in the longitudinal direction at the draw ratios and temperatures in Table 1, then stretched transversely at the draw ratios and temperatures shown in Table 1, and further heat set at 180 ° C. to make a biaxially oriented polyester film.

The thickness of each obtained film is 25 μm. The glass transition temperature (Tg) of the film and the highest temperature peak temperature (Te) of the loss modulus are shown in Table 1, and the evaluation results are shown in Table 2.

Copolymerizable powder Copolymerization Ratio (mol%) Tm (℃) Elongation condition Lateral drawing condition Tg (℃) Te (℃) Te-Tg (℃) Magnification Temperature (℃) Magnification Temperature (℃) Example 1 NDC 18 213 3.2 110 3.3 120 83 105 17 Example 2 NDC 10 232 3.0 115 3.1 125 81 100 19 Example 3 NDC 10 232 3.3 110 3.5 120 81 109 28 Example 4 NDC 6 242 3.0 120 3.1 130 80 108 28 Example 5 CHDM 12 229 3.0 110 3.1 120 79 102 23 Example 6 CHDM 18 212 3.2 100 3.3 110 80 95 15 Example 7 IANDC 66 228 3.0 110 3.1 120 78 98 20 Comparative Example 1 IA 6 243 3.0 110 3.1 120 76 103 27 Comparative Example 2 NDC 20 208 3.2 100 3.3 110 84 97 13 Comparative Example 3 NDC 10 232 3.2 100 3.3 110 81 112 32 Polymer component IA: isophthalic acid NDC: 2,6-naphthalenedicarboxylic acid CHDM: 1,4-cyclohexanedimethanol (the same applies in the following table)

Deep Processing Impact resistance Heat Saturation Resistance Retort Resistance Boseong Comprehensive Evaluation One 2 One 2 Example 1 ○ ○ ○ ○ ○ ◎ ○ ○ Example 2 ○ ○ ○ ○ ○ ◎ ○ ◎ Example 3 ○ ○ ○ ○ ○ ◎ ◎ ◎ Example 4 ○ ○ ○ ○ ○ ◎ ◎ ◎ Example 5 ○ ○ ○ ○ ○ ○ ○ ○ Example 6 ○ ○ ○ ○ ○ ○ ○ ○ Example 7 ○ ○ ○ ○ ○ ○ ○ ○ Comparative Example 1 ○ ○ ○ ○ ○ ◎ △ △ Comparative Example 2 ○ ○ ○ ○ ○ ○ △ △ Comparative Example 3 ○ × - - - - - × "-" In the table means that no evaluation was made.

As can be seen from the evaluation results in Table 2, the cans made using the polyester film of the present invention satisfies the deep cross-processability, heat saturation resistance, retort resistance and impact resistance, and the steering properties, in particular, the replenishment after retort treatment This is excellent.

Examples 8-13 and Comparative Example 4

The unstretched film was dried, melt-extruded and quench-solidified by copolymerizing polyethylene terephthalate (containing 0.24% of spherical silica having a specific viscosity of 0.64, a particle size ratio of 1.1 and an average particle diameter of 0.5 μm) by copolymerizing the components shown in Table 3. Make. The unstretched film is stretched in the longitudinal direction at the draw ratios and temperatures in Table 3, then stretched transversely at the draw ratios and temperatures in Table 3, and further heat set at 170 ° C. to make a biaxially oriented polyester film.

The thickness of each film obtained is 25 μm. Table 4 shows the glass transition temperature (Tg) of the film, the highest temperature peak temperature (Te) of the loss modulus, the X-ray diffraction intensity ratio, the refractive index in the film plane direction, the refractive index in the thickness direction, and the amount of water extract-1, The evaluation results are shown in Table 5.

Copolymerizable powder Copolymerization Ratio (mol%) Melting Point (℃) Elongation condition Lateral drawing condition Magnification Temperature (℃) Magnification Temperature (℃) Comparative Example 4 NDC 20 208 3.5 105 3.6 115 Example 8 NDC 18 213 3.3 100 3.5 110 Example 9 NDC 10 232 3.2 115 3.3 125 Example 10 NDC 6 242 3.0 130 3.1 135 Example 11 CHDM 12 229 3.2 115 3.3 125 Example 12 IANDC 66 228 3.2 120 3.3 130

Tg (℃) Te (℃) Te-Tg (℃) X-ray diffraction intensity ratio Refractive index Water Extract -1 (mg / square inch) Film plane direction (Max / Min) Thickness direction Comparative Example 4 84 100 16 0.38 1.652 / 1.638 1.545 0.20 Example 8 83 103 20 0.35 1.654 / 1.635 1.542 0.16 Example 9 81 107 26 0.13 1.659 / 1.648 1.517 0.10 Example 10 80 107 27 0.15 1.652 / 1.645 1.514 0.10 Example 11 79 104 25 0.22 1.642 / 1.634 1.518 0.14 Example 12 78 100 22 0.23 1.645 / 1.638 1.521 0.20

Deep cross Impact resistance Heat Saturation Resistance Retort Resistance Boseong Comprehensive Evaluation One 2 One 2 Comparative Example 4 ○ ○ ○ ○ ○ ○ △ △ Example 8 ○ ○ ○ ○ ○ ◎ ○ ◎ Example 9 ○ ○ ○ ○ ○ ◎ ◎ ◎ Example 10 ○ ○ ○ ○ ○ ◎ ◎ ◎ Example 11 ○ ○ ○ ○ ○ ○ ○ ○ Example 12 ○ ○ ○ ○ ○ ○ ○ ○

Examples 13 and 14 and Comparative Examples 5 and 6

Copolyethylene terephthalate (containing 0.2 wt% of spherical silica having a specific viscosity of 0.62, a particle size of 1.1, and an average particle diameter of 0.5 μm) prepared by copolymerizing the components shown in Table 6 was melt-extruded and quenched and solidified to form an unstretched film. The unstretched film is stretched and heat set under the conditions of Table 4 to make a biaxially oriented polyester film.

The thickness of each film obtained is 25 μm. Table 7 shows the glass transition temperature (Tg), the highest peak temperature (Te) of the loss modulus, the X-ray diffraction intensity ratio, the refractive index in the film plane direction, the refractive index in the thickness direction, and the amount of water extract-1. .

The evaluation results are shown in Table 8. Excellent results were obtained with films of the invention (Examples 13 and 14) with Tg above 78 ° C. and Te − Tg below 30 ° C., whereas films with Tg below 78 ° C. (Comparative Example 5) were obtained after heat resistance and retort treatment. Poor flavor is bad and Te-Tg is 30 degreeC or more (Comparative Example 6), and moldability is bad.

Copolymerization component Copolymerization Ratio (mol%) Melting Point (℃) Elongation condition Lateral drawing condition Heat setting temperature (℃) Magnification Temperature (℃) Magnification Temperature (℃) Comparative Example 5 IANDC 84 228 3.0 110 3.1 115 180 Example 13 IANDC 48 228 3.1 115 3.2 120 180 Example 14 NDC 10 232 3.2 105 3.3 115 190 Comparative Example 6 NDC 10 232 3.4 120 3.6 130 190

Tg (℃) Te (℃) Te-Tg (℃) X-ray diffraction intensity ratio Refractive index Water Extract -1 (mg / square inch) Film plane direction (Max / Min) Thickness direction Comparative Example 5 77 98 21 0.25 1.642 / 1.632 1.521 0.23 Example 13 79 102 23 0.24 1.644 / 1.640 1.524 0.17 Example 14 81 109 28 0.14 1.654 / 1.649 1.519 0.07 Comparative Example 6 81 113 32 0.12 1.655 / 1.652 1.517 0.05

Deep processability Impact resistance Heat Saturation Resistance Retort Resistance Boseong Comprehensive Evaluation One 2 One 2 Comparative Example 5 ○ ○ ○ ○ ○ ◎ △ △ Example 13 ○ ○ ○ ○ ○ ◎ ◎ ◎ Example 14 ○ ○ ○ ○ ○ ◎ ◎ ◎ Comparative Example 6 ○ × - - - - - × "-" In the table means no evaluation was made.

Examples 15-18

Example 9 A biaxially oriented polyester film having the properties shown in Table 10 (particularly, the X-ray diffraction intensity ratio and refractive index in the film plane direction was changed), except that the stretching and heat setting conditions were changed as shown in Table 9 Make it the same way.

The results are shown in Table 11. The film of the present invention having an X-ray diffraction intensity ratio of 0.10 to 0.40 and a refractive index in the film plane direction of 1.620 to 1.670 in all directions shows excellent results. The comprehensive evaluation is shown in Table 11.

Elongation condition Lateral drawing condition Heat setting temperature (℃) Magnification Temperature (℃) Magnification Temperature (℃) Example 15 3.4 130 3.6 135 160 Example 16 3.0 125 3.1 130 200 Example 17 2.8 125 3.3 130 190 Example 18 2.8 120 3.4 120 170

Tg (℃) Te (℃) Te-Tg (℃) X-ray diffraction intensity ratio Refractive index Water Extract -1 (mg / square inch) Film plane direction (Max / Min) Thickness direction Example 15 81 107 26 0.12 1.661 / 1.649 1.515 0.10 Example 16 81 98 17 0.38 1.638 / 1.630 1.536 0.23 Example 17 81 102 21 0.24 1.660 / 1.628 1.526 0.17 Example 18 81 106 25 0.21 1.667 / 1.632 1.521 0.11

Deep Processing Impact resistance Heat Saturation Resistance Retort Resistance Boseong Comprehensive Evaluation One 2 One 2 Example 15 ○ ○ ○ ○ ○ ◎ ◎ ◎ Example 16 ○ ○ ○ ○ ○ ◎ ◎ ◎ Example 17 ○ ○ ○ ○ ○ ◎ ◎ ◎ Example 18 ○ ○ ○ ○ ○ ◎ ◎ ◎

Examples 19-23 and Comparative Examples 7 and 8

The unstretched film was dried, melt-extruded and quench-solidified by copolymerizing polyethylene terephthalate (containing 0.24% of spherical silica having a specific viscosity of 0.64, a particle size ratio of 1.1 and an average particle diameter of 0.5 μm) by copolymerizing the components shown in Table 12. Make. The unstretched film is stretched in the longitudinal direction at the draw ratios and temperatures in Table 12, then stretched transversely at the draw ratios and temperatures in Table 12, and further heat-set at 170 ° C to form a biaxially oriented polyester film.

The thickness of each film obtained is 25 μm. Table 13 shows the glass transition temperature (Tg) of the film, the highest peak temperature (Te) of the loss modulus, the X-ray diffraction intensity ratio, the plane orientation coefficient, the refractive index in the thickness direction, and the water extract amount-1 in Table 13, and the evaluation results are as follows. Table 14 shows.

Copolymerization component Copolymerization Ratio (mol%) Melting Point (℃) Elongation condition Lateral drawing condition Magnification Temperature (℃) Magnification Temperature (℃) Comparative Example 7 NDC 20 208 3.4 100 3.5 110 Example 19 NDC 18 213 3.4 110 3.5 110 Example 20 NDC 10 232 3.3 120 3.4 130 Example 21 NDC 6 242 2.9 125 3.0 130 Comparative Example 8 NDC 4 248 2.7 120 2.9 125 Example 22 CHDM 12 229 3.2 125 3.3 130 Example 23 IANDC 66 228 3.2 125 3.3 135

Tg (℃) Te (℃) Te-Tg (℃) X-ray diffraction intensity ratio Face orientation coefficient Thickness Refractive Index Water Extract -1 (mg / square inch) Comparative Example 7 84 100 16 0.37 0.106 1.542 0.19 Example 19 83 103 20 0.34 0.104 1.541 0.14 Example 20 81 107 26 0.19 0.138 1.516 0.10 Example 21 80 107 27 0.14 0.135 1.514 0.09 Comparative Example 8 79 107 28 0.16 0.132 1.513 0.09 Example 22 79 102 23 0.24 0.116 1.519 0.18 Example 23 78 99 21 0.25 0.116 1.523 0.21

Deep Processing Impact resistance Heat Saturation Resistance Retort Resistance Boseong Comprehensive Evaluation One 2 One 2 Comparative Example 7 ○ ○ ○ ○ ○ ○ △ △ Example 19 ○ ○ ○ ○ ○ ◎ ○ ◎ Example 20 ○ ○ ○ ○ ○ ◎ ◎ ◎ Example 21 ○ ○ ○ ○ ○ ◎ ◎ ◎ Comparative Example 8 △ × - - - - - × Example 22 ○ ○ ○ ○ ○ ◎ ○ ◎ Example 23 ○ ○ ○ ○ ○ ○ ○ ○ "-" In the table means no evaluation was made.

Examples 24 and 25 and Comparative Examples 9 and 10

The unstretched film was dried, melt-extruded and quench-solidified by copolymerizing polyethylene terephthalate (containing 0.2 wt% of spherical silica having a specific viscosity of 0.62, a particle size of 1.1 and an average particle diameter of 0.5 μm) prepared by copolymerizing the components shown in Table 15. Make. The unstretched film is stretched and heat set under the conditions of Table 15 to make a biaxially oriented polyester film.

The thickness of each film obtained is 25 μm. Table 16 shows the glass transition temperature (Tg) of the film, the highest peak temperature (Te) of the loss modulus, the X-ray diffraction intensity ratio, the plane orientation coefficient s, the refractive index in the film thickness direction, and the amount of ion-exchanged water extract-1. It was.

The evaluation results are shown in Table 16. Excellent results are obtained with the film of the present invention having a Tg of 78 ° C or more and a Te-Tg of 30 ° C or less. Films having a Tg of less than 78 ° C (Comparative Example 9) had poor heat resistance and retardation after retort treatment, and films having a Te-Tg of more than 30 ° C (Comparative Example 10) had poor moldability.

Copolymerizable powder Copolymer (mol%) Melting Point (℃) Elongation condition Lateral drawing condition Heat setting temperature (℃) Magnification Temperature (℃) Magnification Temperature (℃) Comparative Example 9 IANDC 84 228 3.1 110 3.2 115 180 Example 24 IANDC 48 228 3.2 115 3.3 120 180 Example 25 NDC 10 232 3.3 110 3.4 120 190 Comparative Example 10 NDC 10 232 3.5 125 3.6 130 190

Tg (℃) Te (℃) Te-Tg (℃) X-ray diffraction intensity ratio Face orientation coefficient Thickness Refractive Index Water Extract -1 (mg / square inch) Comparative Example 9 77 100 23 0.22 0.121 1.519 0.21 Example 24 79 104 25 0.21 0.124 1.521 0.15 Example 25 81 109 28 0.14 0.133 1.519 0.08 Comparative Example 10 81 113 32 0.12 0.137 1.517 0.05

Deep Processing Impact resistance Heat Saturation Resistance Retort Resistance Boseong Comprehensive Evaluation One 2 One 2 Comparative Example 9 ○ ○ ○ ○ ○ ◎ △ △ Example 24 ○ ○ ○ ○ ○ ◎ ◎ ◎ Example 25 ○ ○ ○ ○ ○ ◎ ◎ ◎ Comparative Example 10 ○ × - - - - - × "-" In the table means no evaluation was made.

Examples 26-29

A biaxially oriented polyester film having the properties shown in Table 19 (particularly, the X-ray diffraction intensity ratio and plane orientation coefficient) was changed, the same method as in Example 20 except that the stretching and heat setting conditions were changed as shown in Table 18. Make it.

The results are shown in Table 20. The film of the present invention having an X-ray diffraction intensity ratio of 0.10 to 0.40 and a plane orientation coefficient of 0.100 to 0.150 shows excellent results. The comprehensive evaluation is shown in Table 20.

Elongation condition Lateral drawing condition Heat setting temperature (℃) Magnification Temperature (℃) Magnification Temperature (℃) Example 26 3.3 125 3.4 130 160 Example 27 2.8 120 3.0 125 190 Example 28 3.1 125 3.2 130 200 Example 29 3.1 100 3.2 105 170

Tg (℃) Te (℃) Te-Tg (℃) X-ray diffraction intensity ratio Face orientation coefficient Thickness Refractive Index Water Extract -1 (mg / square inch) Example 26 81 107 26 0.12 0.140 1.515 0.08 Example 27 81 99 18 0.38 0.106 1.532 0.20 Example 28 81 94 13 0.36 0.102 1.534 0.27 Example 29 81 107 26 0.15 0.148 1.511 0.11

Deep Processing Impact resistance Heat Saturation Resistance Retort Resistance Boseong Comprehensive Evaluation One 2 One 2 Example 26 ○ ○ ○ ○ ○ ◎ ◎ ◎ Example 27 ○ ○ ○ ○ ○ ◎ ◎ ◎ Example 28 ○ ○ ○ ○ ○ ◎ ◎ ◎ Example 29 ○ ○ ○ ○ ○ ◎ ◎ ◎

Examples 30-34 and Comparative Example 11

The unstretched film was dried, melt-extruded and quench-solidified by copolymerizing polyethylene terephthalate (containing 0.2 wt% of spherical silica having a specific viscosity of 0.64, a particle size of 1.1, and an average particle diameter of 0.5 μm) prepared by copolymerizing the components shown in Table 21. Make. The unstretched film is stretched in the longitudinal direction at the draw ratios and temperatures in Table 21, then stretched in the transverse direction at the draw ratios and temperatures in Table 12, and further heat-set at 170 ° C to form a biaxially oriented polyester film.

The thickness of each film obtained is 25 μm. Glass transition temperature (Tg) of film, highest peak temperature of loss modulus (Te), X-ray diffraction intensity ratio, sub peak (Tsm) measured by DSC, refractive index in thickness direction and ion exchange water extract amount of film- 1 is shown in Table 22, and the evaluation results are shown in Table 23.

Copolymerization component Copolymerization Ratio (mol%) Melting Point (℃) Elongation condition Lateral drawing condition Magnification Temperature (℃) Magnification Temperature (℃) Comparative Example 11 NDC 20 208 3.6 110 3.6 115 Example 30 NDC 18 213 3.5 115 3.6 115 Example 31 NDC 12 228 3.2 110 3.3 120 Example 32 NDC 6 242 2.8 120 2.9 125 Example 33 CHDM 12 229 3.1 115 3.2 125 Example 34 IANDC 66 228 3.1 120 3.2 130

Tg (℃) Te (℃) Te-Tg (℃) X-ray diffraction intensity ratio DSC measurement subpeak (℃) Thickness Refractive Index Water Extract -1 (mg / square inch) Comparative Example 11 84 100 16 0.38 170 1.543 0.18 Example 30 83 103 20 0.35 170 1.541 0.14 Example 31 81 107 26 0.19 169 1.519 0.10 Example 32 80 107 27 0.15 168 1.514 0.10 Example 33 79 102 23 0.24 169 1.519 0.20 Example 34 78 98 20 0.25 169 1.523 0.23

Deep Processing Impact resistance Heat Saturation Resistance Retort Resistance Boseong Comprehensive Evaluation One 2 One 2 Comparative Example 11 ○ ○ ○ ○ ○ ○ △ △ Example 30 ○ ○ ○ ○ ○ ◎ ○ ◎ Example 31 ○ ○ ○ ○ ○ ◎ ◎ ◎ Example 32 ○ ○ ○ ○ ○ ◎ ◎ ◎ Example 33 ○ ○ ○ ○ ○ ◎ ○ ◎ Example 34 ○ ○ ○ ○ ○ ○ ○ ○

As can be seen from Table 23, films of the invention (Examples 30 to 34) made of copolyesters having a melting point of 210 to 245 ° C. show excellent results, whereas films made from copolyesters having a melting point of less than 210 ° C. ( Comparative Example 11) is poor in heat resistance and complementarity after retort treatment.

Examples 35 and 36 and Comparative Examples 12 and 13

The unstretched film was dried, melt-extruded and quench-solidified by copolymerizing polyethylene terephthalate (containing 0.2 wt% of spherical silica having a specific viscosity of 0.62, a particle size of 1.1 and an average particle diameter of 0.5 μm) prepared by copolymerizing the components shown in Table 24. Get The unstretched film is stretched and heat set under the conditions of Table 24 to make a biaxially oriented polyester film.

The thickness of each film obtained is 25 μm. Glass transition temperature (Tg) of film, highest peak temperature of loss modulus (Te), X-ray diffraction intensity ratio, sub peak (Tsm) measured by DSC, refractive index in film thickness direction and ion exchange water extract amount-1 Is shown in Table 25.

The evaluation results are shown in Table 26. Excellent results are obtained with films of the invention (Examples 35 and 36) with Tg of 78 ° C. or higher and Te-Tg of 30 ° C. or lower. Films having a Tg of less than 78 ° C (Comparative Example 12) had poor heat resistance and retardation after retort treatment, and films having a Te-Tg of more than 30 ° C (Comparative Example 13) had poor moldability.

Copolymerizable powder Copolymer (mol%) Melting Point (℃) Elongation condition Lateral drawing condition Heat setting temperature (℃) Magnification Temperature (℃) Magnification Temperature (℃) Comparative Example 12 IANDC 84 228 3.1 115 3.2 120 180 Example 35 IANDC 48 228 3.1 120 3.2 125 180 Example 36 NDC 12 228 3.2 100 3.3 110 190 Comparative Example 13 NDC 12 228 3.4 115 3.6 125 190

Tg (℃) Te (℃) Te-Tg (℃) X-ray diffraction intensity ratio DSC measurement sub peak (℃) Thickness Refractive Index Water Extract -1 (mg / square inch) Comparative Example 12 77 98 21 0.25 179 1.521 0.20 Example 35 79 102 23 0.24 179 1.524 0.18 Example 36 81 109 28 0.14 188 1.521 0.08 Comparative Example 13 81 113 32 0.12 188 1.519 0.04

Deep Processing Impact resistance Heat Saturation Resistance Retort Resistance Boseong Comprehensive Evaluation One 2 One 2 Comparative Example 12 ○ ○ ○ ○ ○ ◎ △ △ Example 35 ○ ○ ○ ○ ○ ◎ ◎ ◎ Example 36 ○ ○ ○ ○ ○ ◎ ◎ ◎ Comparative Example 13 ○ × - - - - - × "-" In the table means no evaluation was made.

Examples 37 to 40

A biaxially oriented polyester film having the properties shown in Table 28 (particularly the X-ray diffraction intensity ratio and the sub peak (Tsm) measured by DSC) was changed, except that the stretching and heat setting conditions were changed as shown in Table 27. Made in the same manner as in Example 31.

The results are shown in Table 29. The film of the present invention having an X-ray diffraction intensity ratio of 0.10 to 0.40 and a sub peak (Tsm) measured by DSC of 150 to 205 캜 shows excellent results. The comprehensive evaluation is shown in Table 29.

Elongation condition Lateral drawing condition Heat setting temperature (℃) Magnification Temperature (℃) Magnification Temperature (℃) Example 37 3.4 125 3.6 130 160 Example 38 3.0 120 3.1 125 200 Example 39 3.2 110 3.3 120 155 Example 40 3.2 110 3.3 120 205

Tg (℃) Te (℃) Te-Tg (℃) X-ray diffraction intensity ratio DSC measurement sub peak Thickness Refractive Index Water Extract -1 (mg / square inch) Example 37 81 107 26 0.12 158 1.517 0.09 Example 38 81 98 17 0.38 199 1.538 0.22 Example 39 81 107 26 0.18 152 1.520 0.10 Example 40 81 100 19 0.33 202 1.533 0.18

Deep Processing Impact resistance Heat Saturation Resistance Retort Resistance Boseong Comprehensive Evaluation One 2 One 2 Example 37 ○ ○ ○ ○ ○ ◎ ◎ ◎ Example 38 ○ ○ ○ ○ ○ ◎ ◎ ◎ Example 39 ○ ○ ○ ○ ○ ◎ ◎ ◎ Example 40 ○ ○ ○ ○ ○ ◎ ◎ ◎

Examples 41 to 47 and Comparative Examples 11 to 16

The unstretched film was dried, melt-extruded and quench-solidified by copolymerizing polyethylene terephthalate (containing 0.2 wt% of spherical silica having a specific viscosity of 0.64, a particle size ratio of 1.1 and an average particle diameter of 0.5 μm) prepared by copolymerizing the components shown in Table 30. Get After extending | stretching an unstretched film longitudinally at the draw ratio and temperature of Table 30, it extends laterally at the draw ratio and temperature of Table 30, and further heat-setting at 180 degreeC, and makes a biaxially-oriented polyester film.

The thickness of each film obtained was 25 m, and the evaluation results of the film are shown in Table 31.

Copolymerization component Copolymerization Ratio (mol%) Melting Point (℃) Elongation condition Lateral drawing condition Tg (℃) Te (℃) Te-Tg (℃) F40 / F120 Magnification Temperature (℃) Magnification Temperature (℃) Example 41 NDC 18 213 3.2 110 3.3 120 83 105 17 0.78 Example 42 NDC 10 232 3.0 115 3.1 125 81 100 19 0.75 Example 43 NDC 10 232 3.3 110 3.6 120 81 109 28 0.62 Example 44 NDC 6 242 3.0 120 3.1 130 80 108 28 0.63 Example 45 CHDM 12 229 3.0 110 3.1 120 79 102 23 0.65 Example 46 CHDM 18 212 3.2 100 3.3 110 80 95 15 0.69 Example 47 IANDC 66 228 3.0 110 3.1 120 78 98 20 0.65 Comparative Example 14 IA 6 243 3.0 110 3.1 120 76 103 27 0.64 Comparative Example 15 NDC 20 208 3.2 100 3.3 110 84 97 13 0.78 Comparative Example 16 NDC 10 232 3.2 100 3.3 110 81 112 32 0.67

Deep Processing Impact resistance Heat Saturation Resistance Retort Resistance Boseong Comprehensive Evaluation One 2 One 2 Example 41 ○ ○ ○ ○ ○ ◎ ○ ○ Example 42 ○ ○ ○ ○ ○ ◎ ○ ◎ Example 43 ○ ○ ○ ○ ○ ◎ ◎ ◎ Example 44 ○ ○ ○ ○ ○ ◎ ◎ ◎ Example 45 ○ ○ ○ ○ ○ ○ ○ ○ Example 46 ○ ○ ○ ○ ○ ○ ○ ○ Example 47 ○ ○ ○ ○ ○ ○ ○ ○ Comparative Example 14 ○ ○ ○ ○ ○ ◎ △ △ Example 15 ○ ○ ○ ○ ○ ○ △ △ Example 16 ○ × - - - - - × "-" In the table means no evaluation was made.

Examples 48-52 and Comparative Examples 17-21

As shown in Table 30, 0.2 wt% of copolymerized polyethylene terephthalate (spherical silica having a particle size of 1.1 and an average particle diameter of 0.5 μm was prepared using an acid component, diethylene glycol, an alkali metal compound, a polycondensation catalyst and a phosphorus compound). Containing, hereinafter referred to as PET), dried, melt-extruded and quench-solidified at 280 ° C. to obtain an unstretched film. The unstretched film is stretched 3.0 times in the longitudinal direction and 3.0 times in the transverse direction and heat set at 180 ° C. to make a 25 μm-thick biaxially oriented polyester film. The properties of the film are shown in Table 32 and Table 33.

Comparative Example 22

A biaxially oriented film was prepared in the same manner as in Example 46 except that the melt extrusion temperature was changed to 300 ° C. in the copolymerization-PET preparation. The properties of the film are shown in Table 32 and Table 33. The amount of free glycol ester contained in the biaxially oriented film is higher than the above examples.

Characteristics of the polymer Characteristics of the film Metal and Phosphorus Content in Films Dicarboxylic acid component (molar ratio) DEG component (mol%) Tg (℃) Tm (℃) Polycondensation [η] Amount of free glycol ester (ppm) Water extract amount-2 (mg / square inch) A (ppm) M (mmol%) M + P (mmol%) M / P (mmol% / mmol%) Example 48 TA (90) NDC (10) 1.5 81 232 GeO ₂ 0.70 20 0.05 10 40 60 2.0 Example 49 TA (90) NDC (10) 1.0 82 231 Sb ₂ O ₃ 0.70 20 0.05 10 50 75 2.0 Example 50 TA (90) NDC (10) 3.0 78 226 GeO ₂ 0.70 30 0.06 0 30 45 2.0 Example 51 TA (82) NDC (18) 1.5 83 213 GeO ₂ 0.70 15 0.03 10 40 60 2.0 Example 52 TA (94) NDC (6) 1.5 80 242 GeO ₂ 0.70 25 0.05 10 40 60 2.0 Comparative Example 17 TA (90) NDC (10) 1.5 81 232 GeO ₂ 0.70 60 0.20 10 40 60 2.0 Comparative Example 18 TA (75) NDC (25) 1.5 85 196 GeO ₂ 0.70 10 0.05 10 40 60 2.0 Comparative Example 19 TA (98) NDC (2) 1.5 77 251 GeO ₂ 0.70 50 0.10 10 40 60 2.0 Comparative Example 20 TA (91) AA (9) 1.5 60 228 GeO ₂ 0.70 70 0.40 10 40 60 2.0 Comparative Example 21 TA (94) IA (6) 1.5 76 243 GeO ₂ 0.70 55 0.10 10 40 60 2.0 Comparative Example 22 TA (90) NDC (10) 1.5 81 232 GeO ₂ 0.45 60 0.20 10 40 60 2.0 The abbreviations in the table represent the following substances: TA: terephthalic acid, NDC: 2,6-naphthalenedicarboxylic acid, AA: adipic acid, IA: isophthalic acid, DEG: diethylene glycol Tg: glass transition temperature, Tm: melting point , GeO ₂ : germanium dioxide, Sb ₂ O ₃ : antimony trioxide, A: total amount of alkali metal elements remaining in the film, M: concentration of catalytic metal elements remaining in the film, P: concentration of phosphorus elements remaining in the film The value is the value measured according to the method described above. M + P and M / P are obtained by substituting the above values.

Cohesion Deep Processing Impact resistance Heat embrittlement resistance Retort Resistance Boseong Bubble, wrinkle Heat shrinkage One 2 One 2 Example 48 ○ ○ ○ ○ ○ ○ ○ ◎ ○ Example 49 ○ ○ ○ ○ ○ ○ ○ ◎ ○ Example 50 ○ ○ ○ ○ ○ ○ ○ ◎ ◎ Example 51 ○ ○ ○ ○ ○ ○ ○ ◎ ○ Example 52 ○ ○ ○ ○ ○ ○ ○ ○ ○ Comparative Example 17 ○ ○ ○ ○ ○ ○ ○ ○ △ Comparative Example 18 ○ ○ ○ ○ △ △ △ ○ × Comparative Example 19 △ × - - - - - - - Comparative Example 20 ○ ○ ○ ○ ○ ○ ○ ○ △ Example 21 ○ ○ ○ ○ ○ ○ ○ ◎ △ Example 22 ○ △ × - - - - - -

As can be seen from the results of Table 31, the cans made using the copolyester film of the present invention are satisfactory in terms of deep workability, heat saturation resistance, retort resistance and impact resistance, and are supplemented, especially after retort treatment. Excellent beauty

Claims (25)

(A) (a) 82 to 100 mol% or more of terephthalic acid and 2,6-naphthalenedicarboxylic acid or 2,6-naphthalenedicarboxylic acid and other dicarboxylic acids (to the total amount of all dicarboxylic acid components) S) 0-18 mol% or less and (b) at least 82-100 mol% ethylene glycol and cyclohexanedimethanol or cyclohexanedimethanol in combination with other diols relative to the total amount of all diol components. It is made up of mol% or less and comprises (c) a glass transition temperature of 78 ° C. or higher and (d) a melting point of 210 to 250 ° C. (B) The following relationship between the hottest peak temperature (Te, ° C) and the glass transition temperature (Tg, ° C) of the loss modulus: Te-Tg ≤ 30 It has a biaxially-oriented polyester film for metal plate bonding shaping | molding, characterized by having The film according to claim 1, wherein all dicarboxylic acid components of the copolyester are composed of terephthalic acid and 2,6-naphthalenedicarboxylic acid, and all diol components of the copolyester are composed of ethylene glycol. . The film according to claim 1, wherein the glass transition temperature of the copolyester is in the range of 78 to 90 ° C. The film according to claim 1, wherein the melting point of the copolyester is in the range of 210 to 245 ° C. The film according to claim 1, wherein the film has the following relationship between the highest temperature peak temperature Te of the loss modulus and the glass transition temperature Tg. 15 ≤ Te-Tg ≤ 25. The film of claim 1, having a relationship between the surface 100 and the surface 110 parallel to the film surface: 0.10 ≤ I (110) / I (100) ≤ 0.40 [Wherein I 110 is the X-ray diffraction intensity obtained from the surface 110 and I (100) is the X-ray diffraction intensity obtained from the surface 100]. 7. The film of claim 6 wherein the refractive index in the film plane direction is from 1.620 to 1.670 in all directions. The film according to claim 6, wherein the plane orientation coefficient is 0.100 to 0.150. The film according to claim 6, which has a peak in the temperature range of 150 to 205 ° C. different from the melting point peak in DSC. The film of claim 1, wherein the tensile stress at 40% elongation at 100 ° C. (F40, kgf / mm ² ) and the tensile stress at 120% elongation at 100 ° C. (F120, kgf / mm ² ) satisfy the following relationship: Films characterized by being present on the surface: 0.6 ≤ F40 / F120 ≤ 0.8. The film according to claim 1, wherein the amount of extract obtained by extraction treatment with ion-exchanged water at 121 ° C. for 2 hours is 0.5 mg / square inch (0.0775 mg / cm ² ) or less. (A) (a) 82 to 100 mol% or more of terephthalic acid and 2,6-naphthalenedicarboxylic acid or 2,6-naphthalenedicarboxylic acid and other dicarboxylic acids (to the total amount of all dicarboxylic acid components) (S) 0 to 18 mol% or less, and (b) at least 82 to 100 mol% of ethylene glycol and a combination of cyclohexanedimethanol or cyclohexanedimethanol with other diols relative to the total amount of all diol components. 18 mol% or less, and (c) a copolymerized polyester having a glass transition temperature of 78 ° C. or higher and (d) a melting point of 210 to 250 ° C., (B ') The biaxially-oriented polyester film for metal plate joining molding process containing free dicarboxylic acid diol ester in the quantity of 50 ppm or less. The film according to claim 12, wherein the film contains ethylene glycol at least 90 mol% based on the total amount of all diol components. 13. The film of claim 12 wherein the intrinsic viscosity of the copolyester is in the range of 0.5 to 0.8 dl / g. 13. The film of claim 12 wherein the free dicarboxylic acid diol ester is bis (β-hydroxyethyl) terephthalate. 13. The film of claim 12, wherein the highest peak temperature (Te, ° C) and the glass transition temperature (Tg, ° C) of the loss modulus of the copolyester satisfy the following relationship: Te-Tg ≤ 30. The film of claim 12, wherein the tensile stress at 40% elongation at 100 ° C. (F40, kgf / mm ² ) and the tensile stress at 120% elongation at 100 ° C. (F120, kgf / mm ² ) satisfy the following relationship: Films characterized by being present on the surface: 0.6 ≤ F40 / F120 ≤ 0.8. The film according to claim 12, wherein the amount of extract obtained by extraction treatment with ion-exchanged water at 125 ° C. for 1 hour is 0.1 mg / square inch (0.0155 mg / cm ² ) or less. 13. The film of claim 12, having the following relationship between the surface 100 and the surface 110 parallel to the film surface: 0.10 ≤ I (110) / I (100) ≤ 0.40 [Wherein I 110 is the X-ray diffraction intensity obtained from the surface 110 and I (100) is the X-ray diffraction intensity obtained from the surface 100]. 20. The film of claim 19 wherein the refractive index in the film plane direction is from 1.620 to 1.670 in all directions. 20. The film of claim 19, wherein the plane orientation coefficient is 0.100 to 0.150. 20. The film of claim 19 having a peak in the temperature range of 150 to 205 DEG C different from the melting point in DSC. 13. Film according to claim 1 or 12, having a thickness of 6 to 75 μm. The laminated body is manufactured by bonding a film on a metal plate, The use of the film of Claim 1 or 12 characterized by the above-mentioned. Use of the laminate of claim 24 for deep-machining for producing metal cans.